The present invention relates generally to the high speed winding of filamentary material onto bobbins or tubes to form packages of filamentary material. More particularly, the invention relates to the automated removal of full packages and replacement thereof by empty tubes.
The manufacture of man-made or synthetic filament yarns is typically achieved by extruding a molten polymer, such as polyester, polyamide, etc., through hole(s) in a spinneret and then cooling the filament(s) thus formed. Thereafter, the filaments may be gathered together to form a multi-filament yarn and, possibly after further treatment, are wound onto a tube so that a yarn package is formed.
Winding of the yarn is performed mechanically by winders which rotate one or more tubes on a spindle to wind-up the yarn while traversing the yarn along the tube axis to achieve a uniform thickness of yarn being wound. When winding is completed, a filled tube, hereinafter termed a "package", must be doffed and replaced by an empty tube for a subsequent winding operation.
Such a doffing/donning operation is often performed manually by an operator who (i) severs the yarn; (ii) stops or disengages the rotary drive to the packages; (iii) replaces the packages with empty tubes; (iv) re-establishes the rotary drive; and (v) rethreads the yarn onto the empty tubes. Severing of the filamentary yarn is typically performed with scissors while the inlet of a suction or aspirator gun is held against the yarn at a location upstream of the point of severing. Once the yarn is severed, the tail end is wound onto the yarn package, while the newly formed leading end is sucked into the aspirator and transported to a waste collector.
Replacement of the packages with empty tubes is performed when rotation of the filled package has terminated, whereupon the operator activates an ejection device that pushes packages off the spindle and grasps the filled packages and pulls them from the spindle. The operator then mounts the packages on a transport device, and pushes empty tubes onto the spindle. It would be desirable to eliminate the physical handling of filled packages by operators, not merely from an economical labor-saving standpoint, but also to prevent damage and staining of the yarn if touched by the operator's hands, as well as to permit the winding of large packages that are too heavy to be handled by an operator.
It has heretofore been proposed to mechanize the doffing/donning operation by providing an automated system for removing the filled packages from the winder spindle, inserting empty tubes on the spindle, and transporting the packages to a downstream station for further handling.
For example, a floor-mounted robot-type of mechanism has been developed and employed which (i) cuts and aspirates yarn, (ii) shuts off the spindle motor, (iii) removes the filled packages, (iv) inserts empty tubes onto the spindle, (v) restarts the winder, (vi) rethreads the tubes, and (vii) transports the filled packages to a downstream station. The robot is quite large and extends across three or four positions (winders) even while servicing only one, thereby interfering with any service or maintenance that must be performed on those three or four positions. In order to enable the robot to (i) cut and aspirate yarns at each station, (ii) receive packages and (iii) install empty tubes, it is necessary to achieve a high degree of alignment between the robot and winder. This requires sophisticated equipment, such as a sensor on the robot which senses a target (e.g., a light beam) on the winder to brake the robot. The robot is designed to slightly overshoot the position of alignment and thus must back-track at half speed until again sensing the target. After again overshooting the target, the robot advances at a yet slower speed until resensing the target and halting at an aligned position. Besides requiring sophisticated equipment, such a procedure is time-consuming. In this regard, it will be appreciated that the quantity of robots needed in a plant depends in great part upon the rapidity with which the robot can service each position. The need to achieve precision alignment extends the servicing period. Additional time consumption is caused by the large number of steps which must be performed by the robot, including shutting-off the winder, cutting and aspirating the yarn, and transporting the filled packages to a downstream station.
Other types of automated tube exchange mechanisms are disclosed in U.S. Shippers et al Pat. No. 3,964,723 issued June 22, 1976 and U.S. Shippers Pat. No. 4,023,743 issued May 17, 1977. In the latter patent, a spool-changing carriage 22 moves along rails positioned below a line of winders. A movable spool conveyor extends beneath the carriage. This carriage carries a gripper which simultaneously removes filled packages and captures empty tubes from the spool conveyor. Then the gripper rotates 180.degree. and simultaneously transfers the empty tubes onto the winder spindle and transfers the filled packages to the conveyor.
It will be appreciated that such an arrangement minimizes the accessibility of the winders. That is, by mounting the carriage and conveyor beneath the winders, the winders must be raised to a level which is more difficult for maintenance personnel to reach. Such accessibility is further hampered by the presence of the conveyor, conveyor tracks, and carriage tracks, etc., which are disposed in the immediate vicinity of the winders. Furthermore, the carriage/conveyor arrangement cannot be retro-fit onto existing lines, but rather requires that a new installation be constructed to accommodate the carriage/conveyor support tracks.
The empty tube gripper cylinder employed in that system includes a series of internal fluid-actuated clamping elements for gripping the empty tubes. Such a mechanism greatly exacerabates the overall complexity of the equipment.
The carriage of the above-described system is capable of servicing only winder spindles disposed at a common elevation. On the other hand, many winders currently in use employ spindles positioned at different elevations.
The principal object of the present invention is to provide a method and an apparatus to automatically remove yarn packages and install empty tubes on spinning machine winders without the need for operator presence or attention.
Another object of the present invention is to provide a method and an apparatus for removing yarn packages from the spinning machine winders that are too heavy for humans to handle.
A further object of this invention is to provide a method and an apparatus to transport the packages automatically away from the spinning area and to bring in the empty tubes for automatic installation on winder spindles.
A still further object of the present invention is to provide a means and an apparatus for delivering the packages to an area downstream of spinning where the packages may be automatically picked-up, transported, tested, inspected, sorted and packaged for shipment.
Another object of this invention is to provide an automatic doffing apparatus that takes little space in the spinning area that conveys the packages out of the spinning area above head height so as not to interfere with service and maintenance personnel on the area floor.
A still further object of this invention is to provide an automatic doffing apparatus serving a large number of winder positions and accomplishing this by separating the actions of doffing the winders from the action of transporting the doffed packages away from the spinning area at great speed and paralleling these actions so they overlap or are taking place simultaneously, thus reducing the overall doffing cycle time.
A further object of the present invention is to provide an automatic doffing apparatus that is safe and compatible with the occasional presence of the service and maintenance personnel where the doffing element is slow moving and not threatening to humans and where the fast moving element transporting the packages from the spinning area is safely placed overhead well above any human traffic below.
A still further object of this invention is to provide an automatic doffing apparatus that although capable of being accurately placed in line with a winder spindle is tolerant of considerable misalignment while accepting packages from the winder or installing close tolerance tubes on the winder spindle.